include/linux/trace_events.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2
   3 #ifndef _LINUX_TRACE_EVENT_H
   4 #define _LINUX_TRACE_EVENT_H
   5
   6 #include <linux/ring_buffer.h>
   7 #include <linux/trace_seq.h>
   8 #include <linux/percpu.h>
   9 #include <linux/hardirq.h>
  10 #include <linux/perf_event.h>
  11 #include <linux/tracepoint.h>
  12
  13 struct trace_array;
  14 struct trace_buffer;
  15 struct tracer;
  16 struct dentry;
  17 struct bpf_prog;
  18
  19 const char *trace_print_flags_seq(struct trace_seq *p, const char *delim,
  20                                   unsigned long flags,
  21                                   const struct trace_print_flags *flag_array);
  22
  23 const char *trace_print_symbols_seq(struct trace_seq *p, unsigned long val,
  24                                     const struct trace_print_flags *symbol_array);
  25
  26 #if BITS_PER_LONG == 32
  27 const char *trace_print_flags_seq_u64(struct trace_seq *p, const char *delim,
  28                       unsigned long long flags,
  29                       const struct trace_print_flags_u64 *flag_array);
  30
  31 const char *trace_print_symbols_seq_u64(struct trace_seq *p,
  32                                         unsigned long long val,
  33                                         const struct trace_print_flags_u64
  34                                                                  *symbol_array);
  35 #endif
  36
  37 const char *trace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr,
  38                                     unsigned int bitmask_size);
  39
  40 const char *trace_print_hex_seq(struct trace_seq *p,
  41                                 const unsigned char *buf, int len,
  42                                 bool concatenate);
  43
  44 const char *trace_print_array_seq(struct trace_seq *p,
  45                                    const void *buf, int count,
  46                                    size_t el_size);
  47
  48 struct trace_iterator;
  49 struct trace_event;
  50
  51 int trace_raw_output_prep(struct trace_iterator *iter,
  52                           struct trace_event *event);
  53
  54 /*
  55  * The trace entry - the most basic unit of tracing. This is what
  56  * is printed in the end as a single line in the trace output, such as:
  57  *
  58  *     bash-15816 [01]   235.197585: idle_cpu <- irq_enter
  59  */
  60 struct trace_entry {
  61         unsigned short          type;
  62         unsigned char           flags;
  63         unsigned char           preempt_count;
  64         int                     pid;
  65 };
  66
  67 #define TRACE_EVENT_TYPE_MAX                                            \
  68         ((1 << (sizeof(((struct trace_entry *)0)->type) * 8)) - 1)
  69
  70 /*
  71  * Trace iterator - used by printout routines who present trace
  72  * results to users and which routines might sleep, etc:
  73  */
  74 struct trace_iterator {
  75         struct trace_array      *tr;
  76         struct tracer           *trace;
  77         struct trace_buffer     *trace_buffer;
  78         void                    *private;
  79         int                     cpu_file;
  80         struct mutex            mutex;
  81         struct ring_buffer_iter **buffer_iter;
  82         unsigned long           iter_flags;
  83
  84         /* trace_seq for __print_flags() and __print_symbolic() etc. */
  85         struct trace_seq        tmp_seq;
  86
  87         cpumask_var_t           started;
  88
  89         /* it's true when current open file is snapshot */
  90         bool                    snapshot;
  91
  92         /* The below is zeroed out in pipe_read */
  93         struct trace_seq        seq;
  94         struct trace_entry      *ent;
  95         unsigned long           lost_events;
  96         int                     leftover;
  97         int                     ent_size;
  98         int                     cpu;
  99         u64                     ts;
 100
 101         loff_t                  pos;
 102         long                    idx;
 103
 104         /* All new field here will be zeroed out in pipe_read */
 105 };
 106
 107 enum trace_iter_flags {
 108         TRACE_FILE_LAT_FMT      = 1,
 109         TRACE_FILE_ANNOTATE     = 2,
 110         TRACE_FILE_TIME_IN_NS   = 4,
 111 };
 112
 113
 114 typedef enum print_line_t (*trace_print_func)(struct trace_iterator *iter,
 115                                       int flags, struct trace_event *event);
 116
 117 struct trace_event_functions {
 118         trace_print_func        trace;
 119         trace_print_func        raw;
 120         trace_print_func        hex;
 121         trace_print_func        binary;
 122 };
 123
 124 struct trace_event {
 125         struct hlist_node               node;
 126         struct list_head                list;
 127         int                             type;
 128         struct trace_event_functions    *funcs;
 129 };
 130
 131 extern int register_trace_event(struct trace_event *event);
 132 extern int unregister_trace_event(struct trace_event *event);
 133
 134 /* Return values for print_line callback */
 135 enum print_line_t {
 136         TRACE_TYPE_PARTIAL_LINE = 0,    /* Retry after flushing the seq */
 137         TRACE_TYPE_HANDLED      = 1,
 138         TRACE_TYPE_UNHANDLED    = 2,    /* Relay to other output functions */
 139         TRACE_TYPE_NO_CONSUME   = 3     /* Handled but ask to not consume */
 140 };
 141
 142 enum print_line_t trace_handle_return(struct trace_seq *s);
 143
 144 void tracing_generic_entry_update(struct trace_entry *entry,
 145                                   unsigned long flags,
 146                                   int pc);
 147 struct trace_event_file;
 148
 149 struct ring_buffer_event *
 150 trace_event_buffer_lock_reserve(struct ring_buffer **current_buffer,
 151                                 struct trace_event_file *trace_file,
 152                                 int type, unsigned long len,
 153                                 unsigned long flags, int pc);
 154
 155 #define TRACE_RECORD_CMDLINE    BIT(0)
 156 #define TRACE_RECORD_TGID       BIT(1)
 157
 158 void tracing_record_taskinfo(struct task_struct *task, int flags);
 159 void tracing_record_taskinfo_sched_switch(struct task_struct *prev,
 160                                           struct task_struct *next, int flags);
 161
 162 void tracing_record_cmdline(struct task_struct *task);
 163 void tracing_record_tgid(struct task_struct *task);
 164
 165 int trace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...);
 166
 167 struct event_filter;
 168
 169 enum trace_reg {
 170         TRACE_REG_REGISTER,
 171         TRACE_REG_UNREGISTER,
 172 #ifdef CONFIG_PERF_EVENTS
 173         TRACE_REG_PERF_REGISTER,
 174         TRACE_REG_PERF_UNREGISTER,
 175         TRACE_REG_PERF_OPEN,
 176         TRACE_REG_PERF_CLOSE,
 177         TRACE_REG_PERF_ADD,
 178         TRACE_REG_PERF_DEL,
 179 #endif
 180 };
 181
 182 struct trace_event_call;
 183
 184 struct trace_event_class {
 185         const char              *system;
 186         void                    *probe;
 187 #ifdef CONFIG_PERF_EVENTS
 188         void                    *perf_probe;
 189 #endif
 190         int                     (*reg)(struct trace_event_call *event,
 191                                        enum trace_reg type, void *data);
 192         int                     (*define_fields)(struct trace_event_call *);
 193         struct list_head        *(*get_fields)(struct trace_event_call *);
 194         struct list_head        fields;
 195         int                     (*raw_init)(struct trace_event_call *);
 196 };
 197
 198 extern int trace_event_reg(struct trace_event_call *event,
 199                             enum trace_reg type, void *data);
 200
 201 struct trace_event_buffer {
 202         struct ring_buffer              *buffer;
 203         struct ring_buffer_event        *event;
 204         struct trace_event_file         *trace_file;
 205         void                            *entry;
 206         unsigned long                   flags;
 207         int                             pc;
 208 };
 209
 210 void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
 211                                   struct trace_event_file *trace_file,
 212                                   unsigned long len);
 213
 214 void trace_event_buffer_commit(struct trace_event_buffer *fbuffer);
 215
 216 enum {
 217         TRACE_EVENT_FL_FILTERED_BIT,
 218         TRACE_EVENT_FL_CAP_ANY_BIT,
 219         TRACE_EVENT_FL_NO_SET_FILTER_BIT,
 220         TRACE_EVENT_FL_IGNORE_ENABLE_BIT,
 221         TRACE_EVENT_FL_TRACEPOINT_BIT,
 222         TRACE_EVENT_FL_KPROBE_BIT,
 223         TRACE_EVENT_FL_UPROBE_BIT,
 224 };
 225
 226 /*
 227  * Event flags:
 228  *  FILTERED      - The event has a filter attached
 229  *  CAP_ANY       - Any user can enable for perf
 230  *  NO_SET_FILTER - Set when filter has error and is to be ignored
 231  *  IGNORE_ENABLE - For trace internal events, do not enable with debugfs file
 232  *  TRACEPOINT    - Event is a tracepoint
 233  *  KPROBE        - Event is a kprobe
 234  *  UPROBE        - Event is a uprobe
 235  */
 236 enum {
 237         TRACE_EVENT_FL_FILTERED         = (1 << TRACE_EVENT_FL_FILTERED_BIT),
 238         TRACE_EVENT_FL_CAP_ANY          = (1 << TRACE_EVENT_FL_CAP_ANY_BIT),
 239         TRACE_EVENT_FL_NO_SET_FILTER    = (1 << TRACE_EVENT_FL_NO_SET_FILTER_BIT),
 240         TRACE_EVENT_FL_IGNORE_ENABLE    = (1 << TRACE_EVENT_FL_IGNORE_ENABLE_BIT),
 241         TRACE_EVENT_FL_TRACEPOINT       = (1 << TRACE_EVENT_FL_TRACEPOINT_BIT),
 242         TRACE_EVENT_FL_KPROBE           = (1 << TRACE_EVENT_FL_KPROBE_BIT),
 243         TRACE_EVENT_FL_UPROBE           = (1 << TRACE_EVENT_FL_UPROBE_BIT),
 244 };
 245
 246 #define TRACE_EVENT_FL_UKPROBE (TRACE_EVENT_FL_KPROBE | TRACE_EVENT_FL_UPROBE)
 247
 248 struct trace_event_call {
 249         struct list_head        list;
 250         struct trace_event_class *class;
 251         union {
 252                 char                    *name;
 253                 /* Set TRACE_EVENT_FL_TRACEPOINT flag when using "tp" */
 254                 struct tracepoint       *tp;
 255         };
 256         struct trace_event      event;
 257         char                    *print_fmt;
 258         struct event_filter     *filter;
 259         void                    *mod;
 260         void                    *data;
 261         /*
 262          *   bit 0:             filter_active
 263          *   bit 1:             allow trace by non root (cap any)
 264          *   bit 2:             failed to apply filter
 265          *   bit 3:             trace internal event (do not enable)
 266          *   bit 4:             Event was enabled by module
 267          *   bit 5:             use call filter rather than file filter
 268          *   bit 6:             Event is a tracepoint
 269          */
 270         int                     flags; /* static flags of different events */
 271
 272 #ifdef CONFIG_PERF_EVENTS
 273         int                             perf_refcount;
 274         struct hlist_head __percpu      *perf_events;
 275         struct bpf_prog                 *prog;
 276         struct perf_event               *bpf_prog_owner;
 277
 278         int     (*perf_perm)(struct trace_event_call *,
 279                              struct perf_event *);
 280 #endif
 281 };
 282
 283 static inline const char *
 284 trace_event_name(struct trace_event_call *call)
 285 {
 286         if (call->flags & TRACE_EVENT_FL_TRACEPOINT)
 287                 return call->tp ? call->tp->name : NULL;
 288         else
 289                 return call->name;
 290 }
 291
 292 struct trace_array;
 293 struct trace_subsystem_dir;
 294
 295 enum {
 296         EVENT_FILE_FL_ENABLED_BIT,
 297         EVENT_FILE_FL_RECORDED_CMD_BIT,
 298         EVENT_FILE_FL_RECORDED_TGID_BIT,
 299         EVENT_FILE_FL_FILTERED_BIT,
 300         EVENT_FILE_FL_NO_SET_FILTER_BIT,
 301         EVENT_FILE_FL_SOFT_MODE_BIT,
 302         EVENT_FILE_FL_SOFT_DISABLED_BIT,
 303         EVENT_FILE_FL_TRIGGER_MODE_BIT,
 304         EVENT_FILE_FL_TRIGGER_COND_BIT,
 305         EVENT_FILE_FL_PID_FILTER_BIT,
 306         EVENT_FILE_FL_WAS_ENABLED_BIT,
 307 };
 308
 309 /*
 310  * Event file flags:
 311  *  ENABLED       - The event is enabled
 312  *  RECORDED_CMD  - The comms should be recorded at sched_switch
 313  *  RECORDED_TGID - The tgids should be recorded at sched_switch
 314  *  FILTERED      - The event has a filter attached
 315  *  NO_SET_FILTER - Set when filter has error and is to be ignored
 316  *  SOFT_MODE     - The event is enabled/disabled by SOFT_DISABLED
 317  *  SOFT_DISABLED - When set, do not trace the event (even though its
 318  *                   tracepoint may be enabled)
 319  *  TRIGGER_MODE  - When set, invoke the triggers associated with the event
 320  *  TRIGGER_COND  - When set, one or more triggers has an associated filter
 321  *  PID_FILTER    - When set, the event is filtered based on pid
 322  *  WAS_ENABLED   - Set when enabled to know to clear trace on module removal
 323  */
 324 enum {
 325         EVENT_FILE_FL_ENABLED           = (1 << EVENT_FILE_FL_ENABLED_BIT),
 326         EVENT_FILE_FL_RECORDED_CMD      = (1 << EVENT_FILE_FL_RECORDED_CMD_BIT),
 327         EVENT_FILE_FL_RECORDED_TGID     = (1 << EVENT_FILE_FL_RECORDED_TGID_BIT),
 328         EVENT_FILE_FL_FILTERED          = (1 << EVENT_FILE_FL_FILTERED_BIT),
 329         EVENT_FILE_FL_NO_SET_FILTER     = (1 << EVENT_FILE_FL_NO_SET_FILTER_BIT),
 330         EVENT_FILE_FL_SOFT_MODE         = (1 << EVENT_FILE_FL_SOFT_MODE_BIT),
 331         EVENT_FILE_FL_SOFT_DISABLED     = (1 << EVENT_FILE_FL_SOFT_DISABLED_BIT),
 332         EVENT_FILE_FL_TRIGGER_MODE      = (1 << EVENT_FILE_FL_TRIGGER_MODE_BIT),
 333         EVENT_FILE_FL_TRIGGER_COND      = (1 << EVENT_FILE_FL_TRIGGER_COND_BIT),
 334         EVENT_FILE_FL_PID_FILTER        = (1 << EVENT_FILE_FL_PID_FILTER_BIT),
 335         EVENT_FILE_FL_WAS_ENABLED       = (1 << EVENT_FILE_FL_WAS_ENABLED_BIT),
 336 };
 337
 338 struct trace_event_file {
 339         struct list_head                list;
 340         struct trace_event_call         *event_call;
 341         struct event_filter __rcu       *filter;
 342         struct dentry                   *dir;
 343         struct trace_array              *tr;
 344         struct trace_subsystem_dir      *system;
 345         struct list_head                triggers;
 346
 347         /*
 348          * 32 bit flags:
 349          *   bit 0:             enabled
 350          *   bit 1:             enabled cmd record
 351          *   bit 2:             enable/disable with the soft disable bit
 352          *   bit 3:             soft disabled
 353          *   bit 4:             trigger enabled
 354          *
 355          * Note: The bits must be set atomically to prevent races
 356          * from other writers. Reads of flags do not need to be in
 357          * sync as they occur in critical sections. But the way flags
 358          * is currently used, these changes do not affect the code
 359          * except that when a change is made, it may have a slight
 360          * delay in propagating the changes to other CPUs due to
 361          * caching and such. Which is mostly OK ;-)
 362          */
 363         unsigned long           flags;
 364         atomic_t                sm_ref; /* soft-mode reference counter */
 365         atomic_t                tm_ref; /* trigger-mode reference counter */
 366 };
 367
 368 #define __TRACE_EVENT_FLAGS(name, value)                                \
 369         static int __init trace_init_flags_##name(void)                 \
 370         {                                                               \
 371                 event_##name.flags |= value;                            \
 372                 return 0;                                               \
 373         }                                                               \
 374         early_initcall(trace_init_flags_##name);
 375
 376 #define __TRACE_EVENT_PERF_PERM(name, expr...)                          \
 377         static int perf_perm_##name(struct trace_event_call *tp_event, \
 378                                     struct perf_event *p_event)         \
 379         {                                                               \
 380                 return ({ expr; });                                     \
 381         }                                                               \
 382         static int __init trace_init_perf_perm_##name(void)             \
 383         {                                                               \
 384                 event_##name.perf_perm = &perf_perm_##name;             \
 385                 return 0;                                               \
 386         }                                                               \
 387         early_initcall(trace_init_perf_perm_##name);
 388
 389 #define PERF_MAX_TRACE_SIZE     2048
 390
 391 #define MAX_FILTER_STR_VAL      256     /* Should handle KSYM_SYMBOL_LEN */
 392
 393 enum event_trigger_type {
 394         ETT_NONE                = (0),
 395         ETT_TRACE_ONOFF         = (1 << 0),
 396         ETT_SNAPSHOT            = (1 << 1),
 397         ETT_STACKTRACE          = (1 << 2),
 398         ETT_EVENT_ENABLE        = (1 << 3),
 399         ETT_EVENT_HIST          = (1 << 4),
 400         ETT_HIST_ENABLE         = (1 << 5),
 401 };
 402
 403 extern int filter_match_preds(struct event_filter *filter, void *rec);
 404
 405 extern enum event_trigger_type event_triggers_call(struct trace_event_file *file,
 406                                                    void *rec);
 407 extern void event_triggers_post_call(struct trace_event_file *file,
 408                                      enum event_trigger_type tt,
 409                                      void *rec);
 410
 411 bool trace_event_ignore_this_pid(struct trace_event_file *trace_file);
 412
 413 /**
 414  * trace_trigger_soft_disabled - do triggers and test if soft disabled
 415  * @file: The file pointer of the event to test
 416  *
 417  * If any triggers without filters are attached to this event, they
 418  * will be called here. If the event is soft disabled and has no
 419  * triggers that require testing the fields, it will return true,
 420  * otherwise false.
 421  */
 422 static inline bool
 423 trace_trigger_soft_disabled(struct trace_event_file *file)
 424 {
 425         unsigned long eflags = file->flags;
 426
 427         if (!(eflags & EVENT_FILE_FL_TRIGGER_COND)) {
 428                 if (eflags & EVENT_FILE_FL_TRIGGER_MODE)
 429                         event_triggers_call(file, NULL);
 430                 if (eflags & EVENT_FILE_FL_SOFT_DISABLED)
 431                         return true;
 432                 if (eflags & EVENT_FILE_FL_PID_FILTER)
 433                         return trace_event_ignore_this_pid(file);
 434         }
 435         return false;
 436 }
 437
 438 #ifdef CONFIG_BPF_EVENTS
 439 unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx);
 440 #else
 441 static inline unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx)
 442 {
 443         return 1;
 444 }
 445 #endif
 446
 447 enum {
 448         FILTER_OTHER = 0,
 449         FILTER_STATIC_STRING,
 450         FILTER_DYN_STRING,
 451         FILTER_PTR_STRING,
 452         FILTER_TRACE_FN,
 453         FILTER_COMM,
 454         FILTER_CPU,
 455 };
 456
 457 extern int trace_event_raw_init(struct trace_event_call *call);
 458 extern int trace_define_field(struct trace_event_call *call, const char *type,
 459                               const char *name, int offset, int size,
 460                               int is_signed, int filter_type);
 461 extern int trace_add_event_call(struct trace_event_call *call);
 462 extern int trace_remove_event_call(struct trace_event_call *call);
 463 extern int trace_event_get_offsets(struct trace_event_call *call);
 464
 465 #define is_signed_type(type)    (((type)(-1)) < (type)1)
 466
 467 int trace_set_clr_event(const char *system, const char *event, int set);
 468
 469 /*
 470  * The double __builtin_constant_p is because gcc will give us an error
 471  * if we try to allocate the static variable to fmt if it is not a
 472  * constant. Even with the outer if statement optimizing out.
 473  */
 474 #define event_trace_printk(ip, fmt, args...)                            \
 475 do {                                                                    \
 476         __trace_printk_check_format(fmt, ##args);                       \
 477         tracing_record_cmdline(current);                                \
 478         if (__builtin_constant_p(fmt)) {                                \
 479                 static const char *trace_printk_fmt                     \
 480                   __attribute__((section("__trace_printk_fmt"))) =      \
 481                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 482                                                                         \
 483                 __trace_bprintk(ip, trace_printk_fmt, ##args);          \
 484         } else                                                          \
 485                 __trace_printk(ip, fmt, ##args);                        \
 486 } while (0)
 487
 488 #ifdef CONFIG_PERF_EVENTS
 489 struct perf_event;
 490
 491 DECLARE_PER_CPU(struct pt_regs, perf_trace_regs);
 492
 493 extern int  perf_trace_init(struct perf_event *event);
 494 extern void perf_trace_destroy(struct perf_event *event);
 495 extern int  perf_trace_add(struct perf_event *event, int flags);
 496 extern void perf_trace_del(struct perf_event *event, int flags);
 497 extern int  ftrace_profile_set_filter(struct perf_event *event, int event_id,
 498                                      char *filter_str);
 499 extern void ftrace_profile_free_filter(struct perf_event *event);
 500 void perf_trace_buf_update(void *record, u16 type);
 501 void *perf_trace_buf_alloc(int size, struct pt_regs **regs, int *rctxp);
 502
 503 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
 504                                struct trace_event_call *call, u64 count,
 505                                struct pt_regs *regs, struct hlist_head *head,
 506                                struct task_struct *task);
 507
 508 static inline void
 509 perf_trace_buf_submit(void *raw_data, int size, int rctx, u16 type,
 510                        u64 count, struct pt_regs *regs, void *head,
 511                        struct task_struct *task, struct perf_event *event)
 512 {
 513         perf_tp_event(type, count, raw_data, size, regs, head, rctx, task, event);
 514 }
 515 #endif
 516
 517 #endif /* _LINUX_TRACE_EVENT_H */